grey bottom picture in jpeg

I got a new mac and imported all my photos. At first glance it seems ok but when I go back to 2001-6 some of the photos from an old camera are apparently corrupted. Immediately before or after a bad picture there is a complete and normal photo. If I check get info, it gives the same picture name and information. The picture always starts normally at the top and the bottom of the photo is greyed out. I have opened it and tried to rotate the image but this does nothing.

Can anyone explain what went wrong and is there a fix?

Thanks

levin001